Synthetic DNA locks up drugs in the body – and only cancer has the key
No matter how useful a given drug may be, it’s a problem if it has adverse effects on healthy cells. Now researchers have demonstrated a new way to keep drugs on target, by wrapping them in a transport that can only be unlocked by a certain RNA sequence unique to cancer.
Currently our best treatments for cancer are radiation and chemotherapy, but both have the unfortunate downside of not being particularly selective towards tumors. The radiation and chemicals damage and kill healthy cells throughout the body, leading to a range of unwanted health side effects like fatigue, nausea, and hair loss.
In response, many scientists are investigating ways to make treatments more of a sniper shot than a shotgun blast. For the new study, researchers from the Technical University of Munich (TUM) and the KTH Royal Institute of Technology developed a way to package drugs so they’ll only be unleashed where they’re needed.
The main ingredient is mucin, a protein found in the body in the form of mucus. This is held together with synthetic strands of DNA, and glycerol is added to keep the mucin particles from dissolving, and make them fold up around the active ingredient – the drug itself. Once it’s all together, the DNA strands won’t let the bundle unravel until they encounter the right “key” – a particular microRNA molecule.
In this case, the team chose microRNA that’s only found in cancer. These microRNA strands bind to the DNA and break down the bond holding the package together, releasing the drug. While many cells would take up the packages, the team says only diseased cells would be able to trigger the release of the drugs.
"Cancer cells contain microRNA strands whose structure we know precisely," says Ceren Kimna, lead author of the study. "In order to use them as keys, we modified the lock accordingly by meticulously designing the synthetic DNA strands which stabilize our medication carrier particles.”
Since mucin occurs in the body already, cells should have no problem disposing of the opened packages, the team says.
And cancer is just one application for the technique. The researchers say that the DNA could also be designed to react to microRNA structures found in other diseases like diabetes or hepatitis.
For now, the method is still in the very early stages, and needs to be tested in more complicated tumor models before moving onto animals and, hopefully, humans.
The research was published in the journal ACS Nano.
Source: Technical University of Munich